public class Test {
    public class ListNode {
      int val;
      ListNode next;
      ListNode() {}
      ListNode(int val) { this.val = val; }
      ListNode(int val, ListNode next) { this.val = val; this.next = next; }
    }
    //获取链表长度
    public int Size(ListNode head) {
        int size = 0;
        while (head != null) {
            size++;
            head = head.next;
        }
        return size;
    }
    //获取某一下标位置的节点
    public ListNode get(int index,ListNode head){
        for (int i = 0;i < index;i++){
            head = head.next;
        }
        return head;
    }
    public ListNode reverseBetween(ListNode head, int left, int right) {
        //获取节点
        //将指针指向left下标的节点


    }
}
